Root cause analysis (RCA) is one of the most important elements of problem-solving in quality management.
RCA normally has several goals. The first goal is to discover the root cause of a problem or event. The second goal is to fully understand how to fix, compensate, or learn from any underlying issues within the root cause. The third goal is to apply what we learn from this analysis to systematically prevent future issues or to repeat successes.
Organizations benefit from root cause analysis because it brings together causes from diverse sources and links them via logical relationships. It removes sensitivities, focuses thinking and facilitates review. Effective solutions become clear and opportunities for companywide learning and memory are maximized.
Organizations that practice root cause analysis find ultimate solutions to problems by using one or more specific tools, such as:
5 Whys –The 5 Whys is a method that uses a series of questions to drill down into successive layers of a problem. The basic idea is that each time you ask why, the answer becomes the basis of the next why. It’s a simple tool useful for problems where you don’t need advanced statistics, so you don’t necessarily want to use it for complex problems.
Fishbone Diagram — A fishbone diagram sorts possible causes into various categories that branch off from the original problem. Also called a cause-and-effect or Ishakawa diagram, a fishbone diagram may have multiple sub-causes branching off each identified category.
Failure Mode and Effects Analysis (FMEA) – This RCA method is used during product or process design to explore potential defects or failures. An FMEA chart outlines potential failures, consequences and causes, current controls to prevent each type of failure as well as severity (S), occurrence (O) and detection (D) ratings that allow you to calculate a risk priority number (RPN) for determining further action.
When applied to process analysis, this method is called process failure mode and effects analysis (PFMEA). Many manufacturers use PFMEA findings to inform questions for process audits, using this problem-solving tool to reduce risk at the source.
Pareto Chart – This is a histogram or bar chart combined with a line graph that groups the frequency or cost of different problems to show their relative significance. The bars show frequency in descending order, while the line shows cumulative percentage or total as you move from left to right.
Want to learn more? Tonex offers nearly three dozen courses in Root Cause Analysis Training, such as:
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